Check this succeeded by running spatial update in your terminal. You should get the output:

Current version of the 'spatial' command-line tool: <version number>

Attempting to download the latest version...

3. Set up Unity (optional, unsupported)

Unity is not supported for use with SpatialOS on Linux. It’s possible you can work with
it, but we don’t test it at all. Note that Unity only ‘experimentally’ supports Linux too, so you’re in a real den
of dragons if you decide to play around with this!